Mechanism for truing and dressing grinding wheels



vApril 28, 1931.'

F. J. HOHNHORST ET AL MECHANISM FOR TRUING AD DRESSING GRINDING WHEELS Filed April 18, 1929 Patentedv Apr. 28, 1931 UNlTEb vs'rarlzs PATENT ol-FICE l FERDINAND J. HOHNHOBST AND FERDINAN D J' KROEGEB, OF COVINGTON, KENTUCKY uEcruNrsM ron. 'ranma AND DRESSING GaINnING p Application ined April 1s,

1,544,985, granted to us July 7, 1925, `formechanism for truing and dressing grinding l wheels.

It is essential in precision grinding that the grinding wheels shall be maintained in true form, for instance cylindrical form, and' that the abrading-wheel for truing or dress- 16 ing the grinding wheel shall be maintained in definite relation tothe grinding wheel, in

order that no grooves, ridges or varying sur- 'faces may be imparted to the grinding or polishing surface of the grinding wheel by 20 the truing or dressing wheel.

It is the modern practice to greatly force the rapidity of the truing or dressing operation, and to apply great stresses to the abrading wheel in performing this operation.

We have found that the mountings for rotary abrading wheels performing the truing or dressing operation have in practice, due largely to the great stresses to which the same have been subjected, been short-lived,`

and that such great stresses were conducive to permit the fine dust arising from the truing or dressing operation and caused by the abrasions between the abrading wheel and the inding wheel, to nd access into the bearings for the abrading wheel, resulting in quick wear of such bearings, so that the abrading wheels would, after a comparatively short period of use of the abrading device, not rotate in true cylindrical paths, but would wobble or shift, due to such wear, requiring renewals of bearings and other repairs, adjustments and attention to the device.

It is the object of our invention to provide new and improved means whereby to mount abrading wheels of the character mentioned,

- and to provide new and improved means whereby to protect the bearings from wear.

It is the object of our invention, further,

5 to provide new and improved means for re- 1929. Serial No.- 356,134.

tarding \or preventing the seepage or entrance of fine dust and foreign matter into the bearings; and',.further, to provide new and improved means whereby the arresting means for the dust and other foreign matter automatically accommodates itself to varying positions of the bearingparts due to wear of the bearing, for maintaining its arresting function during such wear.

The invention will be further readily understood from the following description and claims, and from the drawings, in whichA latter:

Fig. 1 is' a side elevation, partly in vertical section, and partly broken away, showing our improved device mounted in a grinding machine and in operative `relation to the grinding wheel. Y

Fig. 2 is an axial section of our improved device, taken on the line 2-2 of Fig. 1; and, dislgg. 3 is a perspective view of the spring The grinding machine may be of any desired kind, and may for instance comprise a frame 11, on which there is a slide 12, adjustable in suitable manner upon the frame, and supporting a grinding wheel 13 in suitable bearings on the slide. A saddle 14 is slidable on guideways 15, 16, on the frame, and is operable by means of a rack 17 with which a pinion' 18, suitably driven, meshes, for providing suitable endwise feed in reverse directions between the work or the5 abrading wheel 19 and the grinding wheel 13, although this endwise feed may be obtained by endwise movementof the grinding wheel with relation to the work or the abrading wheel, as explained `in our aforesaid patent.

A work-supporting table 21 is pivoted by a pivot 22 on the saddle v14. This work-supporting table has thereon the usual head center and tail center between which the work is supported, as explained in our aforesaid patent.

The abrading wheel is preferably of a texture much'harder than the grindlng wheel, and of smaller diameter than the diameter of `the grinding wheel on which it operates. Ro-

tation is imparted to the grinding wheel, for

instance in the direction of the arrow a, by 10 p suitable power means, while -rotation is imparted to the abrading wheel by its contact with the grinding wheel, the direction of rotation of the abrading wheel being indicated 5 by the arrow b.

The grinding wheel during operation becomes impre ated with particles of dirt or metal from t e work being operated on, and becomes com aratively glossy, and thereby loses its grindring effect, its granular structure also. becomin dull at the grinding face, thereby reducing its grinding or polishing properties.

The abrading wheel acts to remove such particles of dirt and metal out of the grinding wheel, and to rou hen and sharpen the granular structure o the grinding face, which operation results in the freeing of such particles of such dirt and metal, and of grit and dust from the grinding face of the grinding wheel and the abrading face of the abrading wheel, which particles, of dirt metal, grit and dust, and other foreign matter, in abrading machines as heretofore constructed, found lodgment in the bearings for the abrading wheel, passing through minute passages in joints between the rotary parts and the stationary parts of the abrading machine, the surfaces of such joints' being in practice quickly enlarged, resulting in quick wear of the bearings, due to such entry of dirt, metal, grit and dust, and other foreign substances.

It is the object of our invention to materially retard or substantially prevent the entrance of such dirt, metal, grit or dust, and such foreign substances, into the bearing, so as to materially enhance the life of the bear- 'he abrading wheel is rotatable about a stub, shaft or axle, hereinafter referred to as an axle, exemplified at 25. The clamp-ends 26, 27, of the axle are suitablyxed in clamp bearings 28, 29, of a head 30, shown as a fork on a shank 31. The axle may be held by a key 32. If desired, 4the clamp end 27 may be omitted, and the axle be suitably secured to a head, by means of its end 26, as exemplified for instance, in our aforesaid Patent No. 1,544,985.

T'he shank 31 is arranged to be secured to the table 21, as by beingreceived in a clamp 35 from the head 36 of which an arm 37 extends, the arm having a jaw 38 thereon coacting with a guide 39. The table is provided with a rail 41, and the head -is provided with a clamping face 42. A Vclamp-plate 43 is loosely connected with the head.

An adjustable stem 44 is located in a bearing 45 in the head, a handle 46 being pivoted to the outer end of the stem by a pin 47. The handle has a cam-face 48, which acts on the clamp-plate 43, for clamping the rail 41be- 65 tween the clamping parts 39, 42 and the 'have absorbent properties. They are exclamp-plate 43 at desirable positions alon the rail.

The axle 25 is provided with a collar 51 which is .preferably fixedxthereto or an in tegral part thereof, although the collar ma be endwise loose on the axle. Ball-bearing 52, 53, are at the respective sides of the col lar. These ball-bearings are preferably ra dial and end-thrust ball-bearings oppositel placed on the axle, the end resistances bein outwardly. A sleeve 54 is received about th axle between the collar 51 and the inner race way 55 of theball-bearing 53. This sleev has spline groove and key connection 56 wit n the axle, compelling the sleeve to rotate wit the axle, but permitting endwise `movemen of the sleeve with relation to the axle. Th inner raceway 55 is provided with an aper ture 57 in which apin 58 fixed to the sleev is received. The ball-bearing 52 has an in ner raceway 59.

A shell 61 is located about the ball-bear ings. The shell is provided with an en d flange 62, forming an end wall provided wit a an annular shoulder 63 and an annular re cess 64. It is further provided with acen tral hole 65, the wall of which is receive al closely about the axle to form a sliding join therewith.

An annular bushing` 67 is located in th bore 68 of the shell, between the outer race ways 69, 70, ofthe ball-bearings 52, 53, fo spacing said outer raceways the desired dis tance from each other.

An end wall 73 is provided for the bore 2 at one end of said bore, the iange 62 formin the end wall for the other end of said bore The end wall 73 has threaded connection 7 with the inner periphery of the shell 61, and is arranged to clamp the outer raceways 69, 70, with the bushing 67 between them, axial direction between the end walls of th bore 68. The end wall 73 is provided with suitable holes 76 for reception of a wrench for rotating the same with relation to the shell.

The end wall 73 is provided with a shoulder 77 and with an annular recess 78, and a central hole 79, the wall of which cooperate with the outer periphery of the axle for forming a joint therewith.

A washer 81 is received in the annular recess 64, and a washer 82 is received in the annular recess 78. These washers are preferably yieldable and resilient, and preferably pressible from the recesses against the axle. They may, for instance, be of felt, which we have found an admirable Amaterial for the purpose.` The washers are provided with holes 83, 84, the walls of which closely hug the outer periphery of the axle.

Disks 91, 92, are provided between the respective ball-bearings and the end walls of the bore in the shell, being located between said ball-bearings and the washers 81, 82.

These disks are preferably exible and somewhat resilient. They are preferably of copper or bronze, and are preferably thin disks to permit the yielding of the inner portions of the same with the wear of the bearings. The disks are 'provided with holes 93, 94, making close jomt with the outer periphery ofthe axle.

The outer edges of these respective disks are clamped between the outer ends of the respective outer raceways of the ball-bearings, and the respective shoulders 63, 77, on the end walls of the bore 68 in which the bearings are located.

A helical spring 95 is located about the sleeve 54 between the collar 51 at one end of the sleeve and a collar or flange 96 at the other end of said sleeve, for normally urging the sleeve away from the collar 51, and vice versa. This exerts a pressure between the A outer ends of the inner raceways of the ballbearings' and the' inner edges of the disks 91, 92, and causes said inner raceways to move axially outward upon any wear in the ballbearings or either ofthe same. Y

The inner cavity of the shell forms a lubricant cavity, communication with which is established by a lubricant passage 97 in the axle, with which a cross-passage 98 in the axle and collar 51 connects, this cross-passage communicating with the cavity. The outer ends of the lubricant passage may be closed by a suitable plug 99. The lubricant lubricates all the surfaces in the shell having movement between them.

If desired, the cushion eii'ect of the washers 81, 82, may lie-supplemented. For this purpose disks 101, 102, which may be of metal, 40 and serve as end walls for the washers, are placed at the outer sides. of said washers, spring disks 103, 104, being placed between the disks 101, 102, and the bottoms of the recesses 64. The disks 103, 104, are exemplified of metal bent into springuform, and compressed when the mounting is assembled, for

exerting pressure in axial direction on the washers 81', 82, this pressure being however substantially lessthan the pressure of the spring 95.

The abradng wheel 19 is lixed about the shell, the shell being received in the central hole of the abradng wheel. One side of the abradng wheel at its inner portion is resisted by an annular liange l107 on the shell 61, a collar 108 being received about said sleeve at the inner portion of the other side of the abradng wheel, a nut 109 being threaded over the threaded end of the outer periphery of theshell for clamping the abradng wheel in place on the shell so as to rotate therewith.

In operation, the shell 61, the end walls 62, 73, thereof, the outer raceways of the ballbearings, the bushing 67, the washers 81, 82, and dlsks 91, 92, 101, 102, 103, 104, rota-te about the axle, the inner raceways of the ballresilient obstructing wall for obstructing the Y entrance of all 'particles of grit, dira-metal, dust and foreign substances past the joint lbetween the walls of the holes 83, 84, Vand the axle, effectively arresting the entrance of foreign matter into the bearings.

The disks 91, 92, form one of the walls of the recesses in which the washers 81, 82, are located, and close joints are maintained between the outer ends of the inner raceways of the ball-bearings and the inner portions of said disks, for providing additional arresting joints for arresting the entrance of any particles of grit, metal, dirt, dust and other foreign substances into the bearings.

The walls of the holes of these disks form arresting joints with the outer periphery of the axle for arresting particles of dirt, grit, metal, dust and other foreign substances from passing the washers 81, 82, toward the bear- 1ngs. Y

In case of wear in the bearings, the inner raceways 59, 55, are respectively moved axially outward to compensate for any Wear which may take place. This insures continuance of proper positioning of the abradng wheel on the axle for true and steady rotation of the abradng wheel. The yieldability or exibility of the disks 91, 92, and the expressibility of the washers 81, 82, permits such movements of vthe 'inner raceways toV take place, and further insures continued intimate,Y

joint relation between the inner walls of the holes 83, 84, in the washers 81, 82, and the axle. The yieldable or iexible properties of the disks permit such movements to take place, and insures themaintenance of close joint relations between the inner portions of said disks andthe inner raceways, soas to maintain an arresting joint for arresting any particles of grit, dirt, dust, metal and foreign substances from entrance into the bearings.

The springs 103, 104, relieve the washers 81, 82 from excess pressure, so as to avoid any binding tendency of the washers upon the axle, and still apply suliicient resistance to the washers to cause the washers to be expressed 'or extended to the axle in case of wear of the walls of the holes in said washers about the axle.

The expressing action upon the washers 81, 82, by such yielding due to wear of the bearings, and such ielding of the inner portions of the disks, re uces the cubic contents of the recesses 64, 78, in which the .washers are located, squeezing the inner walls of the holes of said washers radially inward for more intimate contact with the axle and compensating for any wear there may have been on such inner walls, for insuring maintenance of arresting properties of the joint between said inner' .walls and the axle. j

The tendency is for the lubricant in the cavity of the shell 61 to move outwardly through the joints between the relatively rotating parts and the relatively stationary parts, thus aiding in arresting the passage of particles of dirt, grit, metal, dust and other foreign substances into the bearing.

The use of our invention insures materially longer life of the bearing, and of the trueness of operation of the abrading wheels or other part being rotated, and it has been found in practice that the life of the mounting for the abrading wheel has been increased a great number of times.

Having thus fully described our invention, what we claim as new, and desire to secure by Letters Patent, is:

l. In a device of the character described, the combination of an axle, a member thereabout, a bearing between said member and said axle, and a flexible disk, a radially expressible packing and a complemental wall about said axle at the end of said bearing, the inner periphery of said radially expressible packing normally hugging said axle, said radially expressible packing located between said liexible disk and said complemental wall, and forming arresting means for protecting said bearing and said bearing provided with a part which shifts axially upon wear in said bearing, said shiftable part act- .ing on said flexible disk to iiex said disk axially and thereby radially expressing said expressible packing and thereby causing the inner periphery of said flexible packing to shift radially toward said axle to maintain a hugging relation between said inner periphery of said radially expressible packing and said axle.

2. In a device of the character described,

the combination of an axle, a member there-- about, said member comprising a shell having A a bore and an end wall, a ball-bearing in said bore, va iiexible disk about said axle, a circumferential portion of said iexible disk held between one of the raceways of said ball-beari ng and said end wall, the opposite circumferential portion of said disk coacting with the other raceway-of said ball-bearing for forming a joint, said end wall provided with an annular recess about said shaft, said recess having a circumferential radial wall, and a radially expressible cushion washer between said opposite circumferential portion of said disk and said end wall complemental to said circumferential radial wall, said radially expressible cushion washer arranged to pressed between said opposite circumferential portion of said disk `and said end wall by axial shifting of said other raceway due to wear in said ball-bearing and thereby radially expressing said radially expressible cushion washer toward said circumferential radlal wall.

3. In a device of the character described, the combination of an axle, a member thereabout, said member comprising a shell having a bore and an end wall, a ball-bearing in sald bore, a flexible disk about said axle, a circumferential portion of said iiexible Vdisk held between one of the raceways of said ball-bearing and said end wall, the opposite circumferential portion of said disk coacting with the other raceway of said ball-bearing for forming a joint, said end wall provided with an annular' recess about said shaft, said recess having a circumferential radial wall, a radially expressible cushion washer between said opposite circumferential portion of said disk and said end wall complemental to said circumferential radial wall, said radially expressible cushion washer arranged to be pressed between said opposite circumferential portion of said flexible disk and said end wall by axial shifting of said other raceway due 'to Wear in said ball-bearing and thereby radially expressing said radially expressible cushion washer toward said circumferential radial wall, and resilient means acting on said end Wall for modifying said pressure. upon said cushion washer.

4. In a device of the character described, the combination of an axle and a member thereabout forming a pair 'of elements, said member comprising a s ell having a bore and an end wall, a ball-bearing in said bore, a flexible disk in said bore about said axle, a circumferential portion of said disk held between one of the raceways of said ball-bearing and said end-wall, the opposite circumferential portion of said disk being flexible in axial direction with relation to the firstnamed circumferential portion and coacting with the other raceway of said ball-bearing for forming a joint, said end wall provided with an annular recess about said shaft, said recess having a circumferential radial wall, a spring in said bore acting on said other raceway, and a radially expressible lcushion washer confined between said opposite Hexible circumferential portion of said disk and said end-wall complemental to said circumferential radial wall, the periphery of said radially expressible cushion washer exposed to one of said elements, said radially expressible cushion washer pressed between said opposite axially iiexible circumferential portion of said disk and said end wall by said spring for urging expressing of said periphery of said radially expressible cushion washer radially toward said one of said elements.

5. In a device of the character described,

the combination of an axle and a member thereabout forming a pair of elements, said member comprising a shell having a bore and an end wall, a ball-bearing in said bore',

a iiexible disk in said bore about said axle, a circumferential portion of said disk held between one of the raceways of said ballbearing and -said end-wall, the opposite circumferentlal portion of said disk being flexible in axial direction with relation to its first-named circumferential portion and co-` acting withthe other raceway of said ballbearing for forming a joint, said end wall 'n `provided with an annular recess about said shaft, said recess having a circumferential radial wall, a spring in said bore acting on said other raceway a radially expressible cushion washer confined between said oppodisk and said end-wall complemental to said circumferential' radial wall, the periphery of i ball-bearings in opposite directlons toward said cushion washer exposed to one of said elements, said radially expressible cushion washer pressed between said opposite circumferential flexible portion of said disk and said end wall by said spring for urging said radially expressible periphery of said cushion washer radially toward said one of said elements, and resilient means possessing lighter resilient properties than said. spring acting on said end wall and being complemental to said spring. y

6. In a deviceof'the character described, the combination of an axle, a member thereabout, s aid member comprising a shell having end-walls and a bore between said end walls, said shell located about said axle, opposed ball-bearings in ysaid bore, flexible disks about said axle whose outer portions are fixed between the outer ends of said outer raceways of said ball-bearings and said endwalls, radially expressible cushion washers between the inner portions ofl said iexible.

disks and said end-walls, the inner portions of said disks .coacting with the inner raceways of said ball-bearings to form joints, and arranged to be iexed in axial directions for radially expressing said cushion washers, and a spring between said inner raceways arranged to Hex said inner portions of said flexible disks in' opposite axial directions for radially expressing. said cushion vwashers.-

the combination ofan axle, a member thereabout, said member comprising a bore and an end wall, the inner side of said end wall provided with an annular recesspand an anfor pressing said cushion washer en'wise in,

said recess between said annular movable 6l portion of said disk and said end-wall and y site flexible circumferential portion of said- 7 In a device of the character described,

thereby radially expressing said radially expressible cushion washer.l i

8. In a device of the character described. the combination of a shell comprising a bore and end-walls for said bore, ball-bearings at the respective ends of said bore, the innerl faces of said end-walls provided with outer annular shoulders and inner annular recesses, radially expressible annular cushion washers in vsaid recesses, annular iiexible disks at the respective ends of said bore between said cushion washers and said ballbearings, means for clamping the outer portions of said iiexible disks between said annular shoulders and the outer raceways of said ball-bearings, and a spring in said bore acting to press the inner raceways of said said {iexible disks for radially expressing' said cushion washers.

. 9. In a device of the character described, the combination of a shell comprising a bore and end-walls for said bore, ball-bearings at the respective ends of said bore, the inner faces of said end-walls provided with outer annular shoulders and inner annular recesses, radially expressible annular cushion washers in said recesses, annular iexible disks at the respective ends of said bore between said cushion washers and said ball- 95 bearings, means for clamping the outer portions of said iexible disks between said annular shoulders and the outer raceways of said ball-bearings, a spring in said bore acting to press the inner raceways' ofpsaid ball- 100 bearings 'in opposite directions toward said exible disks for radially expressing said cushion washers, and spring-pressed disks vin said recesses, said radially expressible cushion washers located between said springressed disksand the inner portions of said exible disks, said spring-pressed disks acting on said cushion washers complemental to said inner portions of said flexible disks.

In testimony whereof, we have hereunto signed our names.

FERDINAND J. HOHNHORST. FERDINAND J. KROEGER. 

